An optical connector system configured by a receptacle-side optical connector and a plug-side optical connector is known. When the plug-side optical connector is connected to the receptacle-side optical connector, a ferrule on the plug side abuts a ferrule on the receptacle side so as to make an optical connection.
Patent Literatures 1 to 4 describe optical connector systems including a receptacle-side optical connector and a plug-side optical connector. Note that these literatures also describe that a member is sealed with an O-ring. Further, these literatures also describe a spring (elastic member) that applies pressing force to a plug-side ferrule. Moreover, these literatures also describe a housing and the like that covers optical fibers (naked fibers) extending from a ferrule.